Bump Grpc.Tools from 2.60.0 to 2.64.0 in /dotnet-etcd

Bumps [Grpc.Tools](https://github.com/grpc/grpc) from 2.60.0 to 2.64.0.
- [Release notes](https://github.com/grpc/grpc/releases)
- [Changelog](https://github.com/grpc/grpc/blob/master/doc/grpc_release_schedule.md)
- [Commits](https://github.com/grpc/grpc/commits)

---
updated-dependencies:
- dependency-name: Grpc.Tools
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

dotnet-etcd/dotnet-etcd.csproj

@@ -49,7 +49,7 @@ Advanced uses take advantage of the consistency guarantees to implement database
     <PackageReference Include="Google.Api.CommonProtos" Version="2.13.0" />
     <PackageReference Include="Google.Protobuf" Version="3.25.1" />
     <PackageReference Include="Grpc.Net.Client" Version="2.60.0" />
-    <PackageReference Include="Grpc.Tools" Version="2.60.0">
+    <PackageReference Include="Grpc.Tools" Version="2.64.0">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
     </PackageReference>